Element Builder Gizmo Answer Key

Name: Mariah Bird Date: 08-08-2022 Student Exploration: Element Builder Directions: Follow the instructions to go through the simulation. Respond to the questions andprompts in the orange boxes. Vocabulary: atom, atomic number, electron, electron dot diagram, element, energy level, ion, isotope, mass number, neutron, nucleus, periodic table, proton, radioactive, valence electrons Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. What are some of the different substancesthat make up a pizza? Sauce, cheese, dough 2. What substances make up water? Oxygen and hydrogen 3. What substances make up an iron pot? Iron Elements are pure substances that are made up of one kind of atom . Pizza is not an element because it is a mixture of many substances. Water is a pure substance, but it contains two kinds of atom: oxygen andhydrogen. Iron is an element because it is composed of one kind of atom. Gizmo Warm-up Atoms are tiny particles of matter that are made up of three particles: protons , neutrons , and electrons . The Element Builder Gizmo shows an atom with a single proton. The proton is located in the center of theatom, called the nucleus . 1. Use the arrow buttons ( ) to add protons, neutrons, and electrons to the atom. Press Play ( ). A. Which particles are locatedin the nucleus? Protons B. Which particles orbit aroundthe nucleus? Electorns C. Turn on Show element name . What causes the element name to change? Increased number ofprotons Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Activity A: Subatomicparticles Get the Gizmo ready: ● Use the arrows to create an atom with two protons, two neutrons, and two electrons. ● Turn on Show element name . Question: What are the properties of protons, neutrons, and electrons? 1. Observe: Turn on Show element symbol and Element notation . Three numbers surround the element symbol: the mass number ( A ), electrical charge (no number is displayed if the atom is neutral), and the atomic number ( Z ). 2. Investigate: Watch how the numbers change as you add or remove particles. A. Which number is equal to the number of protons in the atom? Atomic number B. How can you calculate the number of neutrons ( N ) in an atom? Subtract the mass numberby the atomic number. C. Which particle (proton, neutron, or electron) has a Positive charge? proton Negative charge? electron No charge at all? neutron 3. Analyze: An isotope is an alternative form of an element. Each isotope of an element has the same number of protons, but a different number of neutrons. The isotope is represented by the atomic symboland mass number, such as He-4. Some isotopes are stable, while others are radioactive , which means the atoms decay over time and emit radiation. A. What are the stable isotopes of carbon? C+12 and C+13 B. What are the stable isotopes of nitrogen? N+14 and N+15 C. List two radioactive isotopes of oxygen: O+19 and O+20 4. Practice: Use the Gizmo to answer the following questions. A. How many electrons are in a neutral atom of lithium? 3 B. How many neutrons are in an atom of Mg-25? 12 C. What is the mass number of an atom with 5 protons and 7 neutrons? 12 D. When an atom is charged, it is called an ion . How many electrons are in O 2- ? 10 Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

E. How many electrons are in Mg 2+ ? 10 Activity B: Electronarrangements Get the Gizmo ready: ● Create a neutral hydrogen atom (1 proton, 0 neutrons, 1 electron). Question: How are electrons arranged around the nucleus of an atom? 1. Observe: Add electrons to the atom until you have used all the available electrons. How are the electrons arranged? They are not overlapping and are moving in circular orbits around the nucleus. 2. Analyze: Electrons are arranged in orbits called energy levels . The Gizmo shows all of the first two energy levels but only part of the third energy level. A. How many electrons can fit in the first energy level? 2 B. How many electrons can fit in the second energy level? 8 C. How many electrons fit in the part of the third energy level shown? 8 3. Observe: Click Reset ( ). The electrons in the outermost orbit, called valence electrons , help to create chemical bonds. Create a lithium atom (3 protons, 4 neutrons, 3 electrons). How many valence electrons are in a neutral lithium atom? 1 4. Diagram: Turn on Show electron dot diagram . The valence electrons of an atom are shown in an electron dot diagram . Each dot represents a valence electron. ✏ Draw the electron dot diagram for neutral lithium: (Right Click on the element, click “edit”, move the dots around Li) 5. Practice: Turn off Show electron dot diagram . Use the Gizmo to create a neutral atom of each of the following elements. ✏ Draw the electron dot diagram for each: (Right Click on the picture, click “edit”, move the dots around the element symbols) When you are finished, turn on Show electron dot diagram and check your answers. 6. Extend your thinking: Many chemical properties are determined by the number of valence electrons. Elements with the same number of valence electrons will have similar properties. Which element has similar properties to lithium? Na Beryllium? Mg Explain: Their valence electron count is same. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Extension: The periodic table Get the Gizmo ready: ● Create a neutral hydrogen atom.● If you have access to a periodic table, open it now. (Not required.) Question: The 117 or so known elements are arranged in the periodic table. Why does the periodictable have the shape it has? 1. Form a hypothesis: Look at the first three rows of the periodic table below. Why do you think the elements are arranged the way that they are? Valence electron groups move from left to right. 2. ✏ Draw diagrams: Either hand draw in the space below or edit using the drawing tool to create an electron dot diagram for each of the elements below. Use the Gizmo to help you do this. To check your work, turn on Show electron dot diagram . ✏ (Right Click on the picture, click “edit”, move the dots around the element symbols) 3. Analyze: What do the elements in each column of the periodic table have in common? They have the same amount of valence electrons, except for He, but it is ful 4. Draw conclusions: How is the periodic table organized? In columns of common valenceelectron numbers, and rows going from left to right in orderof proton numbers Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved